UNDERSTANDING THE SELF-RECONFIGURATION PROPERTIES OF A NOVEL SPINEL-TYPE HIGH-ENTROPY CATALYST

High-entropy oxides (HEOs), known for their excellent thermodynamic stability due to their high-entropy effect. In this study, high-entropy (NixAlCoCrMn)3O4 oxides of spinel structure were synthesized by sol-gel method. This HEO has a self-reconfiguration properties in the reaction, and its internal Ni and Co ions exsolve to form a uniformly dispersed NiCot alloy on the surface. The increase of Ni content promotes the exsolution of Ni and Co ions from the interior of the spinel. The high-entropy with a large number of oxygen vacancies not only possesses a stable structure to limit the migration of NiCo alloys, but also enhances the hydrogen overflow. In the CO methanation reaction, it has 99% CO conversion with 87% methane selectivity within 400 oC, and it is stable in the long-term test. This work provides a new idea for exploring the use of high-entropy materials to improve thermal catalytic activity and stability.